1. Field of the Invention
This invention, in certain aspects, is directed to power systems; such plants that use methanol in a feedstock; and to methods using such systems to produce electricity.
2. Description of Related Art
The prior art discloses a wide variety of plants and apparatuses for generating electricity using gas turbines. U.S. Pat. No. 4,148,185 discusses the generation of power from the combustion of hydrogen and oxygen cryogenic propellants for the electrolytic release of hydrogen from water to produce oxygen which can also be stored for subsequent combustion to generate power when needed. The separately stored oxygen and hydrogen are combusted together in the presence of a combustion flame coolant (water) to develop a motive fluid (steam) which is first passed through a heat exchanger and then to a turbine inlet. The motive fluid is exhausted from the turbine and reheated in the heat exchanger via the first passage therethrough and then delivered to the inlet of a second turbine. It is then exhausted into a condenser producing waste heat with a portion being re-introduced into the combustor for again cooling the combustion process. Such a system has a motive fluid inlet temperature of 2100° F. or above (a typical gas turbine inlet temperature), the inlet temperature to the preceding heat exchanger is at least as high as the initial inlet temperature to the first turbine plus the temperature rise required in the heat exchanger to raise the exhaust motive fluid from the first turbine t the inlet temperature of the second turbine. With the present turbine inlet temperatures being in the range of 2100°, the heat exchanger inlet temperature is up to 3,000° F. This temperature requirement places design restrictions on the heat exchanger that are difficult to accommodate economically and still provide the long-life expected of equipment in power generating systems.
U.S. Pat. No. 4,148,185 discloses a gas turbine power generation system using high pressure hydrogen and oxygen as the fuel for the gas turbines with the combustion process cooled by the introduction of water or steam so that the combustion temperature range is acceptable. A series of gas turbine engines are connected in series-flow communication so that the reheat of the motive fluid (the combustion of oxygen and hydrogen producing a motive fluid of steam) for the second and subsequent turbines of the system is accomplished by directing the exhaust steam of the preceding turbine into the next downstream combustor wherein the steam is reheated by the combustion therein to the next turbine inlet temperature. Such reheating process can continue for sufficient stages until the pressure of the steam exhaust is at generally atmospheric pressure. The steam is finally exhausted through a heat exchanger to pre-heat the pressurized coolant water to at least partially convert it to steam (which conversion is completed by the combustion in the first combustion chamber or by a two-stage combustion therein) for entry into the initial combustor to cool the combustion process. The use of the combination reheat and the exhaust recuperation in the gas turbine system with hydrogen and oxygen as the combustion fuels maintains the temperature on the various parts, including the rotating members of the turbine engines, within acceptable limits for long-life operation and also increases the efficiency of the over-all power generation system.
U.S. Pat. No. 5,622,043 discloses an electric power generation with a gas turbine subsystem free of a compressor; a compressor subsystem with an air heater remote from the gas turbine subsystem having an inlet receiving air and an outlet furnishing heated compressed air after heating by the air heater; and a compressed air line interlinking the outlet and said gas turbine subsystem; the gas turbine subsystem having a plenum connected to the compressed air line; a burn chamber having a compressed air inlet connected to the plenum and a fuel inlet; a gas expander connected to the burn chamber; and an electrical generator connected to the gas expander; a steam generator having a heat inlet connected to the gas expander and a steam outlet; a first steam turbine having a steam inlet connected to the steam outlet; and a drive shaft connected to the electrical generator.